CA2500346C - Polyimide blends for gas separation membranes - Google Patents

Polyimide blends for gas separation membranes Download PDF

Info

Publication number
CA2500346C
CA2500346C CA 2500346 CA2500346A CA2500346C CA 2500346 C CA2500346 C CA 2500346C CA 2500346 CA2500346 CA 2500346 CA 2500346 A CA2500346 A CA 2500346A CA 2500346 C CA2500346 C CA 2500346C
Authority
CA
Canada
Prior art keywords
formula
membrane
type
repeating units
copolyimide
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CA 2500346
Other languages
French (fr)
Other versions
CA2500346A1 (en
Inventor
Okan Max Ekiner
John W. Simmons
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Original Assignee
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to US43027502P priority Critical
Priority to US60/430,275 priority
Priority to US10/642,407 priority
Priority to US10/642,407 priority patent/US7018445B2/en
Application filed by LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude filed Critical LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Priority to PCT/IB2003/004769 priority patent/WO2004050223A2/en
Publication of CA2500346A1 publication Critical patent/CA2500346A1/en
Application granted granted Critical
Publication of CA2500346C publication Critical patent/CA2500346C/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D71/00Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06Organic material
    • B01D71/58Other polymers having nitrogen in the main chain, with or without oxygen or carbon only
    • B01D71/62Polycondensates having nitrogen-containing heterocyclic rings in the main chain
    • B01D71/64Polyimides; Polyamide-imides; Polyester-imides; Polyamide acids or similar polyimide precursors
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D53/00Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/22Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by diffusion
    • B01D53/228Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by diffusion characterised by specific membranes
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08LCOMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L79/00Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen with or without oxygen or carbon only, not provided for in groups C08L61/00 - C08L77/00
    • C08L79/04Polycondensates having nitrogen-containing heterocyclic rings in the main chain; Polyhydrazides; Polyamide acids or similar polyimide precursors
    • C08L79/08Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08LCOMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2205/00Polymer mixtures characterised by other features
    • C08L2205/02Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group
    • Y02C10/10

Abstract

The present invention provides a selectively gas permeable membrane that has a superior combination of permeability and selectively. The membrane composition includes a Type 1 copolyimide uniformly blended with a Type 2 copolyimide, which polymers are defined by chemical structure more specifically in this disclosure. The invention also provides a method of using the membrane of the copolyimide blend to separate components of gas mixtures.

Description

POLYIMIDE BLENDS FOR GAS SEPARATION MEMBRANES
FIELD OF THE INVENTION

This invention relates to improved membranes for the separation of gases from blends of specific polyimide polymers. Membranes fabricated from these blends exhibit a particularly useful combination of gas-separating properties, especially for the separation of carbon dioxide from hydrocarbons.

BACKGROUND OF THE INVENTION
Permselective membranes for gas separation are known and used commercially in applications such as the production of oxygen-enriched air, production of nitrogen-enriched-air for inerting and blanketing, separation of carbon dioxide from methane or nitrogen for the upgrading of natural gas streams, and the separation of hydrogen from various petrochemical and oil refining streams. The separation of gases by polymeric membranes is thought to depend on the size of the gas molecules and the physical or chemical interaction of the gas with the material of the membrane. For certain gas streams, one or more component or minor contaminant may exhibit a strong interaction with the material of the membrane, which can plasticize the membrane. This can result in reduced production rate and selectivity, and ultimately, loss of membrane performance. A membrane with a good balance of high production rate and selectivity for the gases of interest, and persistently good separation performance despite long-term contact with aggressive stream composition, pressure and temperature conditions is highly desired.

U.S. Pat. No. 4,705,540 discloses highly permeable polyimide gas separation membranes prepared from phenylene diamines having substituents on all positions ortho to the amine functions and a rigid dianhydride or mixtures thereof, specifically pyromellitic dianhydride (PMDA) and 4,4'-(hexafluoroisopropylidene)-bis(phthalic anhydride) (6FDA). These polyimides form membranes with high gas permeabilities but fairly low permselectivities. These polyimides are also sensitive to various organic solvents.

CONFIRMATION COPY

U.S. Pat. No. 4,717,393 shows that polyimides incorporating at least in part 3,3',4,4'-benzophenone tetracarboxylic dianhydride and phenylene diamines having substituents on all positions ortho to the amine functions can be photochemically crosslinked. Membranes formed from such photochemically crosslinked polyimides have improved environmental stability and superior gas selectivity than uncrosslinked polyimide. However, photochemical crosslinking is not a practical method for fabricating gas separation membranes cost-effectively.

U.S. Pat. No. 4,880,442 discloses highly permeable polyimide gas separation membranes prepared from phenylene diamines having substituents on all positions ortho to the amine functions and essentially non-rigid dianhydrides. These polyimides again exhibit high gas permeabilities, but low permselectivities.

Bos et. al., AIChE Journal, 47,1088 (2001), report that polymer blends of Matrimid 5218 polyimide (3,3',4,4'-benzophenone tetracarboxylic dianhydride and diaminophenylindane) and copolyimide P84 [copolyimide of 3,3',4,4'-benzophenone tetracarboxylic dianhydride and 80% toluenediisocyanate/20% 4,4'-methylene-bis(phenylisocyanate)] can increase the stability of the membrane against carbon dioxide plasticization when compared to the plain Matrimid 5218 membrane. They do not disclose any other polyimide blends used for gas separation however.

U. S. Patent No. 5,055,116 describes a blend of aromatic polyimides, in which the proportion of the polymer components is adjusted to achieve certain permeability and selectivity of a polymer membrane. The final properties of a new polymer membrane may be predicted so that a membrane with those desired final properties could then be manufactured. U.S. Patent No. 5,055,116 indicates that the gas transport properties of the membrane prepared from the polyimide blends are predictable and the membrane may be "engineered" to achieve the desired final properties. To the contrary, the gas transport properties of the present invention are unpredictable and surprisingly good.
U.S. Patent No. 5,635,067 discloses a fluid separation membrane based on a blend of two distinct polyimides. One is the copolymer derived from the co-condensation of benzophenone 3,3',4,4'-tetracarboxylic acid dianhydride (BTDA) and optionally pyromellitic dianhydride (PMDA) with a mixture of toluene diisocyanate and/or 4,4'-methylene-bis(phenylisocyanate). The other is Matrimid 5218 polyimide.

The permeation properties of miscible polymer blends can be estimated from the following equation 1 (D. R. Paul and S. Newman, "Polymer Blends", Vol. 1, Chapter 10, p. 460, Academic Press, New York, 1978, B.G. Ranby, J. Polymer Science, Part C
51 p.
89, 1975, A. E. Barnabeo, W.S. Creasy, L.M. Robeson, J. Polymer Science, 13, p. 1979, 1975):

lnaB (p;lna1 (1) where:

aB is the blend permeability or selectivity, 0, is the volume fraction of component i, and a; is the permeability or selectivity of each blend component.

For most blends cited by Paul and Newman, measured permeation performance corresponded reasonably well with permeation performance calculated by Equation 1.
Therefore significant deviations of actual performance either over or under calculated performance predicted by Equation 1 indicates unusual behavior of the blend.

It is desirable to have polymeric gas separation membranes that exhibit high gas permeation rates while maintaining high relative gas selectivity. However, prior art membrane materials generally compromise one for the other. A major challenge for researchers in this field has been to develop materials that show either an increase in permeability with little sacrifice in selectivity, or an increase in selectivity with little sacrifice in permeability.

SUMMARY OF THE INVENTION
Accordingly, The present invention provides a membrane for gas separation comprising a blend of at least one polymer of a Type 1 copolyimide and at least one polymer of a Type 2 copolyimide in which the Type 1 copolyimide comprises repeating units of formula I

O O

K
-R, -N\,R2 N-O O
(I) in which R2 is a moiety having a composition selected from the group consisting of formula A, formula B, formula C and a mixture thereof, O -b-d- O Z O

(A) (B) (C) Z is a moiety having a composition selected from the group consisting of formula L, formula M, formula N and a mixture thereof, and /c\ 0 -s-II
(L) (M) (N) Rt is a moiety having a composition selected from the group consisting of formula Q, formula S, formula T, and a mixture thereof, (Q) (S) (T) in which the Type 2 copolyimide comprises the repeating units of formulas IIa and IIb C C C C
C --Ar-N \ II /Ra\cN - -Ai'-N \c/Rb\c/N

O O O O
(IIa) (IIb) in which Ar is a moiety having a composition selected from the group consisting of formula U, formula V, and a mixture thereof, X
o x XZ
X1 X3 Xl X3 (U) (V) in which X, X1, X2, X3 independently are hydrogen or an alkyl group having 1 to 6 carbon 5 atoms, provided that at least two of X, X1, X2, or X3 on each of U and V are an alkyl group, Ar' is any aromatic moiety, Ra and Rb each independently have composition of formulas A, B, C, D or a mixture thereof, and a 0 0 o Z o (A) (B) (C) )r-( o (D) Z is a moiety having composition selected. from the group consisting of formula L, formula M, formula N and a mixture thereof.

' 0 II

(M) (N) (L) This invention also provides a method of separating one or more gases from a gas mixture comprising (a) providing a gas separation membrane comprising a blend of at least one polymer of a Type 1 copolyimide and at least one polymer of a Type 2 copolyimide in which the Type I and Type 2 eopolyimides are as defined above, (b) contacting the gas mixture with one side of the gas separation membrane thereby causing more preferentially permeable gases of the mixture to permeate the membrane faster than less preferentially permeable gases to form a permeate gas mixture enriched in the more preferentially permeable gases on the opposite side of the membrane and a retentate gas mixture depleted in the more preferentially permeable gases on the one side of the membrane, and (c) withdrawing the permeate gas mixture and the retentate gas mixture separately from the membrane.

In accordance with an aspect of the present invention, there is provided a membrane for gas separation comprising a blend of at least one polymer of a Type 1 copolyimide and at least one polymer of a Type 2 copolyimide in which the Type 1 copolyimide comprises repeating units of formula I

O O
K 'A
-R1-N\[rR N-O O
(I) in which R2 is a moiety having a composition selected from the group consisting of formula A, formula B, formula C and a mixture thereof, 0 0 0 o Z o (A) (B) (C) Z is a moiety having a composition selected from the group consisting of formula L, formula M, formula N and a mixture thereof; and II II
O", -S-O
(L) (M) (N) Rl is a moiety having a composition selected from the group consisting of formula Q, formula S, formula T, and a mixture thereof, 6a ~C~~

(Q) (S) (T) in which the Type 2 copolyimide comprises the repeating units of formulas IIa and IIb C C C C 1.11 IN, I'll -Ar-N\ N- -Air-N\ N
C C C C
11 11 11 il (IIa) (IIb) in which Ar is a moiety having a composition selected from the group consisting of formula U, formula V, and a mixture thereof, and X

X1 X3 Xl X3 (U) (V) in which X, X1, X2, X3 independently are hydrogen or an alkyl group having 1 to 6 carbon atoms, provided that at least two of X, X1, X2, or X3 on each of U and V are an alkyl group, Ar' is any aromatic moiety, Ra and Rb each independently have composition of formulas A, B, C, D or a mixture thereof, 6b -b-d- O Z O

(A) (B) (C) O O

(D) Z is a moiety having composition selected from the group consisting of formula L, formula M, formula N and a mixture thereof, and /C\ O\ -S-II
O
(L) (M) (N) the ratio of Type 1 copolyimide to Type 2 copolyimide is greater than 0.2.
In accordance with another aspect of the present invention, there is provided the membrane of the present invention in which the Type 1 copolyimide comprises repeating units of formula Ia.

O O
C
-Rl -N aUgN-O
O p (Ia) 6c In accordance with another aspect of the present invention, there is provided the membrane of the present invention in which R1 is formula Q in about 16% of the repeating units, formula S in about 64% of the repeating units and formula T in about 20% of the repeating units.
In accordance with another aspect of the present invention, there is provided the membrane of the present invention in which the Type 1 copolyimide comprises repeating units of formula lb O O

-RI-N O N-O O
(Ib) In accordance with another aspect of the present invention, there is provided the membrane of the present invention in which Rl is a composition of formula a in about 1-99 % of the repeating units, and of formula s in a complementary amount totaling 100 % of the repeating units.
In accordance with another aspect of the present invention, there is provided the membrane of the present invention in which the Type 1 copolyimide comprises repeating units having composition of formula la and repeating units having composition of formula lb C

(Ia) (Ib) in which units of formula lb constitute about 1 - 99% of the total repeating units of formulas Ia and lb and in which Rl is a composition of formula Q in about 1-99% of the repeating units, and of formula s in a complementary amount totaling 100% of the repeating units.
In accordance with another aspect of the present invention, there is provided the membrane of the present invention in which the moiety Rl has a composition of formula Q in 6d about 20 % of the repeating units, and of formula s in about 80 % of the repeating units, and in which repeating units of formula lb are about 40% of the total of repeating units of formulas la and lb.
In accordance with another aspect of the present invention, there is provided the membrane of the present invention in which the ratio of Type 1 copolyimide to Type 2 copolyimide is greater than 1Ø
In accordance with another aspect of the present invention, there is provided the membrane of the present invention in which repeating units of formula IIa are at least 25 % of the total repeating units of formula IIa and IIb.
In accordance with another aspect of the present invention, there is provided the membrane of the present invention in which repeating units of formula IIa are at least 50% of the total repeating units of formula IIa and IIb.
In accordance with another aspect of the present invention, there is provided the membrane of the present invention in which the Type 2 copolyimide is formed by polycondensation of an aromatic amine selected from the group consisting of 2,4-diaminomesitylene, 3,7-diamino-2,8-dimethyldiphenylsulfone and a mixture thereof, and a dianhydride selected from the group consisting of pyromellitic dianhydride, 3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride, 3,3',4,4'-biphenyl tetracarboxylic dianhydride, 4,4'-(2,2,2-trifluoro-l-(trifluoromethyl)ethylidine)bis(1,2-benzene dicarboxylic acid dianhydride) and a mixture thereof.
In accordance with another aspect of the present invention, there is provided the membrane of the present invention in which the membrane is an asymmetric membrane.
In accordance with another aspect of the present invention, there is provided the membrane of the present invention in which the membrane is a hollow fiber.
In accordance with another aspect of the present invention, there is provided a method of separating one or more gases from a gas mixture comprising (a) providing a gas separation membrane comprising a blend of at least one polymer of a Type 1 copolyimide and at least one polymer of a Type 2 copolyimide in which the Type 1 copolyimide comprises repeating units of formula I

6e O O
K
-RI-N),R? N-O O
(I) in which R2 is a moiety having a composition selected from the group consisting of formula A, formula B, formula C and a mixture thereof, O -b-d- -b---b--d-(A) (B) (C) Z is a moiety having a composition selected from the group consisting of formula L, formula M, formula N and a mixture thereof; and /C\ 0 -s-II

(L) (M) (N) Rl is a moiety having a composition selected from the group consisting of formula Q, formula S, formula T, and a mixture thereof, )9~-(Q) (S) (T) in which the Type 2 copolyimide comprises the repeating units of formulas IIa and IIb 6f II II II II
C \ /C\
-Ar-N /C\ R. /\ N- -Ar-N N-/\C/ ~C/Rb\C O O O O

(IIa) (IIb) in which Ar is a moiety having a composition selected from the group consisting of formula U, formula V, and a mixture thereof, and x (U) (V) in which X, X1, X2, X3 independently are hydrogen or an alkyl group having 1 to 6 carbon atoms, provided that at least two of X, X1, X2, or X3 on each of U and V are an alkyl group, Ar' is any aromatic moiety, Ra and Rb each independently have composition of formulas A, B, C, D or a mixture thereof, O O O O Z O
(A) (B) (C) 6g O

(D) Z is a moiety having composition selected from the group consisting of formula L, formula M, formula N and a mixture thereof, and ~~ II
~C\ 0\ -S-O

(L) (M) (N) the ratio of Type 1 copolyimide to Type 2 copolyimide is greater than 0.2, (b) contacting the gas mixture with one side of the gas separation membrane thereby causing more preferentially permeable gases of the mixture to permeate the membrane faster than less preferentially permeable gases to form a permeate gas mixture enriched in the more preferentially permeable gases on the opposite side of the membrane and a retentate gas mixture depleted in the more preferentially permeable gases on the one side of the membrane, and (c) withdrawing the permeate gas mixture and the retentate gas mixture separately from the membrane.

In accordance with another aspect of the present invention, there is provided the method of the present invention in which the gas mixture comprises carbon dioxide and methane.

DETAILED DESCRIPTION OF THE INVENTION
The membranes that exhibit an excellent combination of high permselectivity and permeability for the separation of gases according to the present invention are prepared from blends of selected polyimide copolymers. That is, the blends comprise a Type 1 6h copolyimide and a Type 2 copolyimide, as are defined more particularly herein.
Preferably, the material of the membrane consists essentially of the blend of these copolyimides. Provided that they do not significantly adversely affect the separation performance of the membrane, other components can be present in the blend such as, processing aids, chemical and thermal stabilizers and the like.

The Type 1 copolyimide comprises repeating units of formula I
Io O

-Rt -N)rR N-K
O O
(I) in which R2 is a moiety having composition selected from the group consisting of formula A, formula B, formula C and a mixture thereof, O -b-d- O Z O

(A) (B) (C) Z is a moiety having a composition selected from the group consisting of formula L, formula M, formula N and a mixture thereof; and I) IL
-s-II

(L) (M) (N) Rl is a moiety having a composition selected from the group consisting of formula Q, formula S, formula T, and a mixture thereof.

-0-CH2 o (Q) (S) (T) In a preferred embodiment, the repeating units of the Type 1 copolyimide have the composition of formula Ia.

O O
-Rl -N O O N-C

(Ia) A preferred polymer of this composition in which it is understood that R1 is formula Q in about 16 % of the repeating units, formula S in about 64 % of the repeating units and formula T in about 20 % of the repeating units is available from HP
Polymer GmbH under the tradename P84. P84 is believed to be derived from the condensation reaction of benzophenone tetracarboxylic dianhydride (BTDA, 100 mole %) with a mixture of 2,4-toluene diisocyanate (2,4-TDI, 64 mole %), 2,6-toluene diisocyanate (2,6-TDI, 16 mole %) and 4,4'-methylene-bis(phenylisocyanate) (MDI, 20 mole %).

In another preferred embodiment, the Type 1 copolyimide comprises repeating units of formula lb.

O
(1b) Preference is given to using the Type 1 copolyimide of formula lb in which Rl is a composition of formula Q in about 1-99 % of the repeating units, and of formula S in a complementary amount totaling 100 % of the repeating units.

In yet another preferred embodiment, the Type 1 copolyimide is a copolymer comprising repeating units of both formula Ia and lb in which units of formula lb constitute about 1 - 99 % of the total repeating units of formulas la and lb.
A polymer of this structure is available from HP Polymer GmbH under the tradename P84-HT325.
P84-HT325 is believed to have repeating units according to formulas la and lb in which the moiety Rl is a composition of formula Q in about 20 % of the repeating units and of formula S in about 80 % of the repeating units, and in which repeating units of formula Ib constitute about 40 % of the total repeating units of formulas la and Ib.
P84-HT325 is believed to be derived from the condensation reaction of benzophenone tetracarboxylic dianhydride (BTDA, 60 mole %) and pyromellitic dianhydride (PMDA, 40 mole %) with 2,4-toluene diisocyanate (2,4-TDI, 80 mole %) and 2,6-toluene diisocyanate (2,6-TDI, 20 mole %).

The Type 2 polyimide comprises repeating units having composition of formulas IIa and IIb:

o 0 0 0 -Ar-N R N - -qf-N\ N
C a\C C/Rb\C

(IIa) (Iib) in which Ar is a moiety having a composition selected from the group consisting of formula U, formula V, and a mixture thereof, X

X, X3 Xt X3 (U) (V) in which X, X1, X2, X3 independently are hydrogen or alkyl groups having 1 to 6 carbon atoms, provided that at least two of X, X1, X2, or X3 on each of U and V are an alkyl group, Ar' is any aromatic moiety, Ra and Rb each independently have composition of formulas A, B, C, D or a mixture thereof, and O O O O Z O
(A) (B) (C) O

(D) Z is a moiety having composition selected from the group consisting of formula L, formula M, formula N and a mixture thereof.

(1 11 C\ 0 -S-O
(L) (M) (N) In the Type 2 polyimide, the repeating unit of formula IIa should be at least about 25%, and preferably at least about 50% of the total repeating units of formula IIa and formula Ilb. Ar' can be the same as or different from Ar.

The polyimides of this invention should have a weight average molecular weight within the range of about 23,000 to about 400,000 and preferably about 50,000 to about 280,000.

The blend of Type 1 and Type II copolyimides should be uniform and can be formed from the component copolyimides in conventional ways. For example, the Type 1 and Type 2 copolyimides can be synthesized separately and melt compounded or mixed in solution by dissolving each copolyimide in one or more suitable solvents. If the blend is solvent mixed, the solution can be stored or used directly in subsequent membrane fabrication steps or the solvent can be removed to provide a solid blend for later use. If the blend is prepared by melt compounding, the resulting blend can be dissolved in a suitable solvent for subsequent membrane fabrication.
Uniformity of the dry (i.e., solvent-free) blend either before or after membrane formation can be checked by detecting only a single compositional dependent glass transition temperature lying between the glass transition temperatures of the constituent components.
Differential scanning calorimetry and dynamic mechanical analysis can be used to measure glass transition temperature.

Preferably, the blend is formed by dissolving the Type 1 and Type 2 copolyimides in separate solutions, combining the solutions and agitating the combined solutions to obtain a dissolved blend. Mild heating to temperatures in the range of about 50 to 100 C can optionally be used to accelerate dissolution of the components. The polyimide blend is sufficiently soluble in solvents typically used for processing into suitable gas separation membranes. The ratio of Type 1 copolyimide to Type 2 copolyimide in the blend is preferably greater than about 0.2, and more preferably at least about 1Ø

The polyimides described herein are made by methods well known in the art.
Type 1 polyimides can conveniently be made by polycondensation of an appropriate diisocyanate with approximately an equimolar amount of an appropriate dianhydride.
Alternatively, Type 1 polyimides can be made by polycondensation of equimolar amounts of a dianhydride and a diamine to form a polyamic acid followed by chemical or thermal dehydration to form the polyimide. The diisocyanates, diamines and dianhydrides useful for making the Type 1 copolyimides of interest are usually available commercially. Type 2 polyimides are typically prepared by the dianhydride/diamine reaction process just mentioned because the diamines are more readily available than the corresponding diisocyanates.

The preferred Type 1 and Type 2 polyimides are soluble in a wide range of common organic solvents including most amide solvents, that are typically used for the formation of polymeric membranes, such as N-methyl pyrrolidone ("NMP") and in-cresol. This is a great advantage for the ease of fabrication of industrially useful gas separation membranes.

To be economically practical, the separation membrane usually comprises a very thin selective layer that forms part of a thicker structure. This may be, for example, an integral asymmetric membrane, comprising a dense skin region that forms the selective layer and a micro-porous support region. Such membranes are described, for example, in U.S. 5,015,270 to Ekiner. As a further, and preferred, alternative, the membrane may be a composite membrane, that is, a membrane having multiple layers. Composite membranes typically comprise a porous but non-selective support membrane, which provides mechanical strength, coated with a thin selective layer of another material that is primarily responsible for the separation properties. Typically, such a composite membrane is made by solution-casting (or spinning in the case of hollow fibers) the support membrane, then solution-coating the selective layer in a separate step.
Alternatively, hollow-fiber composite membranes can be made by co-extrusion spinning of both the support material and the separating layer simultaneously as described in U. S.
Patent No. 5,085,676 to Ekiner. The polyimide blends are utilized in the selectively permeable layer of the membrane according to the present invention. The support layer of a composite membrane can be free of the copolyimide blend.

The membranes of the invention can be fabricated into any membrane form by any appropriate conventional methods. For illustrative purposes, a method to prepare membranes in accordance with this invention is generally described as follows.
Type 1 and Type 2 copolyimide compositions are selected and are combined in dry particulate form in a dry mix of desired proportion, e.g., 65% Type 1 and 35% Type 2. The solid polymer powder or flake is dissolved in a suitable solvent such as N-methylpyrrolidone at approximately 20-30% polymer content. The polymer blend solution is cast as a sheet at the desired thickness onto a flat support layer (for flat sheet membranes), or extruded through a conventional hollow fiber spinneret (for hollow fiber membranes). If a uniformly dense membrane is desired, the solvent is slowly removed by heating or other means of evaporation. If an asymmetric membrane is desired, the film or fiber structure is quenched in a liquid that is a non-solvent for the polymer and that is miscible with the solvent for the polyimide. Alternatively, if a composite membrane is desired, the polymer is cast or extruded over a porous support of another material in either flat film or hollow fiber form. The separating layer of the composite membrane can be a dense ultra-thin or asymmetric film.

The resulting membranes may be mounted in any convenient type of housing or vessel adapted to provide a supply of the feed gas, and removal of the permeate and residue gas. The vessel also provides a high-pressure side (for the feed gas and residue gas) and a low-pressure side of the membrane (for the permeate gas). For example, flat-sheet membranes can be stacked in plate-and-frame modules or wound in spiral-wound modules. Hollow-fiber membranes are typically potted with a thermoset resin in cylindrical housings. The final membrane separation unit comprises one or more membrane modules, which may be housed individually in pressure vessels or multiple elements may be mounted together in a sealed housing of appropriate diameter and length.

The gas permeation rate (flux) usually varies inversely with selectivity in membrane separations of preferentially permeable gases from other gases in a multi-component gas mixture within many classes of separation membrane materials.
This relationship is generally true for all glassy or crystalline, high glass transition temperature polymers, such as polyimides, polyesters, or polyamides. That is, conventional gas separation membranes tend to exhibit either high gas flux with low gas selectivity or high selectivity at low gas flux.

Type 1 and Type 2 copolyimides have characteristics that limit their utility for use in gas separation membranes. Type 1 copolyimides have generally low gas permeability although they exhibit good selectivity. Type 2 copolyimides provide generally low selectivity with high permeability. One of skill in the gas separation membrane art understands that the selectivity of a blend of selectively permeable polymers should be close to the value predicted by equation 1, above. Contrary to expectation, it has been discovered that blends of a Type 1 polymer and a Type polymer provide significantly greater permeability than the Type 1 polymer alone. This occurs without a significant reduction in selectivity. Blend theory predicts that the low selectivity of Type 2 copolyimide should depress the selectivity of the blend to a greater extent than has been found to be the case. Therefore, the blend of Type 1 and Type 2 copolyimides exhibits a serendipitous synergistic effect to provide a superior balance of flux and selectivity for important industrial gas separations.

Moreover, it is well known in the art that many chemically different polyimides are mutually incompatible and do not form homogeneous blends. Fortuitously and in contrast to conventional wisdom, the polymer blends of this invention are miscible in the compositional ranges of interest. This conclusion is based upon evidence of a single glass transition temperature, perfectly clear polymer solutions, and perfectly clear dense polymer films of the blends. A further benefit derived from blending the Type 1 and Type 2 copolyimides according to this invention is that hollow fiber gas separation membranes formed from the blend exhibit improved mechanical properties relative to exclusively Type 1 copolyimide composition fibers.

Membranes from blends of these polyimides enable an attractive combination of carbon dioxide permeability and permselectivity for carbon dioxide over methane, nitrogen, and the like. The membranes exhibit little or no plasticization by carbon dioxide or aliphatic hydrocarbons, and are thus especially useful for the removal of carbon dioxide from industrially significant gas streams, such as in natural gas sweetening. Even at high operating pressure, membranes prepared from such polyimide blends possess an excellent balance of gas permeation rates and selectivity of one gas over other gases in the multi-component gas mixture.

EXAMPLES
This invention is now illustrated by examples of certain representative, non-limiting embodiments thereof, wherein all parts, proportions and percentages are by weight unless otherwise indicated. All units of weight and measure not originally obtained in SI units have been converted to SI units.

Polyimide supply and synthesis P84 and P84-HT325 polyimides (Type 1) were obtained from HP-Polymer GmbH in both the flake and powder forms.

To synthesize Type 2 copolyimides, a 250mL 3-necked round-bottomed flask, equipped with a mechanical stirrer, a nitrogen inlet, and a Dean-Stark trap was flame dried under a nitrogen atmosphere and allowed to cool to ambient temperature.
The aromatic diamine reactant was dissolved in a polar solvent NMP or N,N'-dimethylacetamide (DMAC). The dianhydride reactant was added portion wise to the reaction vessel, which was stirred rapidly. The ratio of diamine to dianhydride was 1:1 to ensure the highest molecular weight. More NMP was added to the reaction vessel to achieve total solids concentration of about 15-20%. The reaction mixture was stirred at room temperature for 2 hours under a nitrogen atmosphere. Liquid o-dichlorobenzene (ODCB) or toluene was then added and the solution was heated and held at 150-for 5-25 hours to achieve azeoptropic removal of the water. The polymer was then precipitated into water or methanol, ground up in a blender, washed three times with methanol and then twice with water. The polymer was air dried in a vacuum oven at 150-220 C. for at least 2 hours.

Film Preparation A 20% solution of the polyimide in either NMP or m-cresol was cast onto a glass plate at 100-120 C using a 38x10-5 in (15 mil) knife gap. The film was dried on the plate at this temperature for 1-2 hours, removed from the plate, cooled to room temperature and air-dried overnight. The film was further dried in a vacuum oven at about 68 kPa (20 inches Hg) at 220 C for 3 days under a nitrogen atmosphere.
A final film thickness of between 2 x 10"5 and 5 x 10-5 in (1-2 mils) was thus obtained.

Dense Film Testing To measure the gas-separation performance of the polymer films a sample disk was cut from the polymer film and tested in a 47 mm ultrafiltration permeation cell (Millipore) modified for gas permeation measurement, with 2.1 MPa (300 psig) mixed-gas 20:80 C02/CH4 feed, 6-10 mmHg permeate pressure and 35 C temperature. The feed flowrate was set high enough to ensure very low conversion of the feed into permeate in the range of about 2-10 cm3 (standard temperature and pressure "STP")/min.
Sufficient time was allowed to ensure steady-state permeation. The composition of the feed and permeate streams was measured by gas chromatography with a thermal conductivity detector. The permeate composition was 85-95% CO2. The flowrate through the membrane was derived from the rate of increase of the permeate pressure with a Baratron pressure sensor. The permeabilities of CO2 and CH4 were calculated from the flowrate measurement normalized by the partial pressure difference across the membrane and by the area and thickness of the film sample, and expressed in Barrers. A
Barrer is a unit of gas permeability defined as 10"10 cm3 (STP) = cm /(sec =
cm3 = cmHg).
Selectivity was calculated as the ratio of the pure component permeabilities.
Comparative Example 1:

A dense film of P84 polymer was cast from a solution of 20% P84 and 80%
NMP. The film preparation technique above was modified in that the film was dried at 200 C in a vacuum oven for four days. The thickness of the dry film was 0.075 mm.

Two sample disks were cut from the film and tested by the above-described procedure modified in that the feed flowrate was set at approximately 5 cm3 (STP)/min to ensure very low conversion of the feed into permeate. The test was run for 20 hours before measurement, to ensure steady-state permeation. The permeate composition was 92.1% CO2. The average CO2 permeability of the two film samples was 2.3 Barrers. The average CO2/CH4 selectivity was 47.1.

Comparative Examples 2-8: Dense Film Samples The procedure of Comparative Example 1 was repeated except that different polymers were substituted for P84. The polymers used, the average CO2 permeability of two film samples and the average CO2/CH4 selectivity for each example are shown in Table 1.

Examples 1 - 12: Dense Film Samples Dense films of various Type 1/Type 2 polymer blends were cast from solutions comprising 20% total polymer and 80% NMP using the film preparation technique above. The technique was modified in that the film was dried at 200 C in a vacuum oven for four days. The thickness of the dry film was 0.100 mm. Four sample disks were cut from the film and tested by the method in Comparative Example 1 with 2.1 MPa (300 psig) mixed-gas 20:80 C02/CH4 feed, 6-8 mmHg permeate pressure and 35 C
temperature. The average CO2 permeability and C02/CH4 selectivity for each sample is reported in Table 1.

For each of the membranes formed from polymer blends, i.e., Exs. 1-12, the selectivity of the membrane for carbon dioxide relative to methane was calculated by equation 1, above. The actual selectivity obtained by measurement was divided by the calculated value and these ratios are also presented in Table 1.

Examples 1-12 demonstrate that membranes of Type 1/Type 2 polymer blends exhibit an unexpectedly favorable combination of permeability and selectivity in comparison to membranes of either Type 1 polymers or Type 2 polymers alone.
The permeabilities and selectivities of the Type 1/Type 2 polymer blend membranes are largely within ranges of the corresponding Type 1 and Type 2 composition membranes.
However, selectivities provided by the Type 1 polymers (Comp. Exs. 1 and 2) are surprisingly only slightly diminished by adding lower-selectivity Type 2 polymers while the permeabilities of the blend composition membranes are close to the values calculated by equation 1. Example 9 is a slight exception but the membrane composition includes a very large amount of the Type 2 copolyimide.

In every example, the permeability of the Type 1/Type 2 polymer blend membrane was significantly higher than that of the Type 1 composition membrane. All of the operative example selectivities were higher than predicted by equation 1, above.
The deviation from theoretical selectivity was usually at least 15%, and in Exs. 3 and 12 as much as about 50% greater than predicted. Although some of the examples the selectivity of the Type 1/Type 2 blend membrane was between the selectivity of the Type 1 and Type 2 compositions, in a significant number of cases, the selectivity of the blend composition membrane was about as high or higher than the selectivity of membranes formed from Type 1 or Type 2 polymer alone. See Exs. 2, 3, 5, 11 and 12.

Thus the combination of Type 1 and Type 2 copolyimides have a synergistic effect on gas permeation selectivity in membrane separations. This synergy provides a beneficial combination of selectivity and permeability of such magnitude that membranes of blends of Type 1 and Type 2 polymers are commercially useful while membranes of either Type 1 polymer or Type 2 polymer remain commercially unattractive.
Table 1 Selectivity Ratio Type 1 Type 2 Typel:Type 2 Permeability Selectivity aMeasured Example Polymer Polymer Polymer PCO2 a=PC02/PCH4 -Ratio (Barrers) UCalculated Comp. Ex. 1 P84 --- 1:0 2.3 47.1 Comp. Ex. 2 P84 HT325 --- 1:0 6.7 48.8 Comp. Ex. 3 --- A 0:1 310 23 Comp. Ex. 4 B 0:1 65 40.3 Comp. Ex. 5 --- C 0:1 39 43.2 Comp. Ex. 6 --- D 0:1 746 22.1 Comp. Ex. 7 --- E 0:1 455 24.8 Comp. Ex. 8 P84 + P84HT325 1:1 3.3 43 0.90 Ex. 1 P84 A 1:1 30 39.7 1.21 Ex.2 P84 A 3:1 6.2 48 1.22 Ex.3 P84 D 4:1 3.6 63 1.56 Ex.4 P84 E 3:1 8 43 1.07 Ex.5 P84HT325 A 4:1 11.7 48.6 1.16 Ex.6 P84HT325 A 3:1 11.6 43.2 1.07 Ex.7 P84HT325 A 2:1 15.8 44.9 1.18 Ex.8 P84HT325 A 1:1 27.1 39.4 1.18 Ex.9 P84HT325 A 1:3 115 32 1.15 Ex.10 P84HT325 B 1:1 29 45.6 1.03 Ex. 11 P84HT325 C 3:1 9 54.3 1.15 Ex.12 P84HT325 D 1:1 10.5 48 1.46 Table 2 Code Composition Materials A DAM + PMDA/BPDA (1:1) B TSN + 6FDA/BPDA (1:1) C DAM/TSN (1:1) + DSDA
D DAM + PMDA/BTDA (3:1) E DAM + PMDABTDA (6:1) Abbreviations DAM 2,4-diaminomesitylene TSN 3,7-diamino-2,8-dimethyldiphenylsulfone or o-tolidine sulfone PMDA pyromellitic dianhydride DSDA 3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride BPDA 3,3',4,4'-biphenyl tetracarboxylic dianhydride 6FDA 4,4'-(2,2,2-trifluoro-l-(trifluoromethyl)ethylidine)bis(1,2-benzene dicarboxylic acid dianhydride) Comparative Example 9: Hollow Fiber of P84:P84HT325 A spin dope formulation containing 32% P84/P84HT325 polymer blend (1:1 wt ratio), 9.6% tetramethylenesulfone (TMS) and 1.6% acetic anhydride in NMP was prepared. The dope was extruded at 85 C at flowrate of 180 cm3 / hour through a spinneret with fiber channel dimensions of outer diameter 559 microns and inner diameter 254 microns. A solution containing 85% NMP in water was injected at a rate of 33 cm3 / hour through the spinneret to form the bore of the fiber. The nascent fiber traveled through an air gap length of 2.5 cm at room temperature into a water coagulant bath at 8 C and was wound up at a rate of 50 in / min. The water-wet fiber was rinsed with running water at 50 C for about 12 hours and then sequentially exchanged with methanol and hexane as taught in US 4,080,744 and US 4,120,098. Then the fiber was dried at 100 C in a vacuum oven for one hour.

The untreated fibers were tested for permeation of pure CO2 and CH4 gases separately in a hollow fiber gas separation module. The procedure was similar to that for the dense films, above except that the feed gas on the shell side was maintained at 0.35 MPa (50 psig) at 23 C. The CO2 permeance was 110 gas permeation units (GPU) and the CO2 / CH4 selectivity was 25.

The fibers were treated to seal defects in the dense separating layer by contacting the outer surfaces of the fibers for 30 min. with a 2% weight solution of Sylgard 184 (Dow Corning Corp) in isooctane. The fibers were dried in a vacuum oven at 100 C.
The treated fibers were tested as above and found to have CO2 permeance of 36 GPU
and CO2 / CH4 selectivity of 55. These same treated fibers were also tested with a 10:90 ratio mixture of CO2 and CH4 feed at 35 C and 2.1 MPa (300 psig). Separation performance was CO2 permeance of 14 GPU and CO2 / CH4 selectivity of 45. This selectivity agrees well with the intrinsic selectivity of 43 of the P84:P84HT325 (1:1) blend dense film as reported in Comparative Example 8 above.

Example 13: Hollow Fiber of P84:Polymer D (4:1) Blend A spin dope formulation containing 32% P-84:Polymer D blend in 4:1 ratio, 9.6% TMS and 1.6% acetic anhydride in NMP was prepared. The dope was extruded at 92 C at flow rate of 180 cm3/hour through a spinneret with fiber channel dimensions of outer diameter 559 microns and inner diameter 254 microns. A solution containing 82.5% weight NMP in water was injected through the spinneret to form the bore of the fiber at a flow rate of 33 cm3/hour. The nascent fiber traveled through an air gap length of 5 cm at room temperature into a water coagulant bath at 7 C and was wound up at a rate of 50 m/min. The fibers were washed, solvent exchanged with methanol and hexane, and dried as in Comparative Example 9. They were tested with a 10:90 ratio CO2 / CH4 gas mixture feed at 35 C and 2.1 MPa (300 psig) for CO2 and CH4 permeation. Separation properties of the untreated fibers were CO2 permeance of 99 GPU and CO2 / CH4 selectivity of 29. The fibers were treated as in Comparative Example 9 to seal defects and were determined to have CO2 permeance of 62 GP
and CO2 / CH4 selectivity of 44 after post treatment.

Example 14: Hollow Fiber of P84:Polymer E (3:1) Blend A spin dope formulation was spun into hollow fibers as in Ex. 13 except that the 32 % polymer in the dope was 3:1 ratio of P-84: Polymer E blend. Also the nascent fiber traveled through an air gap length of 2.5 cm at room temperature into a water coagulant bath at 8 C and were washed, solvent exchanged with methanol and hexane, and dried as in Comparative Example 9. As tested with 10:90 ratio mixed gas feed of CO2 /
CH4 at 35"C and 2.1 MPa (300 psig) the untreated fiber permeation properties were CO2 permeance of 89 GPU and CO2 / CH4 selectivity of 25. After treatment to seal defects as in Comparative Example 9 the fibers were determined to have CO2 permeance of GPU and CO2 / CH4 selectivity of 46 after post treatment.
Example 15: Hollow Fiber of P84:Polymer A (3:1) Blend The procedure of Ex. 13 was repeated except that the spin dope formulation contained 31% P-84: Polymer A (3:1) polymer blend, 9.3% TMS and 1.55% acetic anhydride in NMP, fiber extrusion rate was 200 cm3 /hour, spinneret fiber channel dimensions were outer diameter 838 microns and inner diameter 406 microns, spinning temperature was 84 C and the nascent fiber traveled through an air gap length of 1 cm.
The fibers were washed, solvent exchanged with methanol and hexane, and dried as in Comparative Example 9. The untreated fibers were tested as in Ex. 13 and found to have CO2 permeance of 124 GPU and CO2 / CH4 selectivity of 35. After post treatment as in Comparative Ex. 9 CO2 permeance GPU and CO2 / CH4 selectivity were 41 and 33, respectively.

While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made. The scope of the claims should not be limited by the preferred embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.

Claims (15)

1. A membrane for gas separation comprising a blend of at least one polymer of a Type 1 copolyimide and at least one polymer of a Type 2 copolyimide in which the Type 1 copolyimide comprises repeating units of formula I

in which R2 is a moiety having a composition selected from the group consisting of formula A, formula B, formula C and a mixture thereof, Z is a moiety having a composition selected from the group consisting of formula L, formula M, formula N and a mixture thereof; and R1 is a moiety having a composition selected from the group consisting of formula Q, formula S, formula T, and a mixture thereof, in which the Type 2 copolyimide comprises the repeating units of formulas IIa and IIb in which Ar is a moiety having a composition selected from the group consisting of formula U, formula V, and a mixture thereof, and in which X, X1, X2, X3 independently are hydrogen or an alkyl group having 1 to 6 carbon atoms, provided that at least two of X, X1, X2, or X3 on each of U and V are an alkyl group, Ar' is any aromatic moiety, R a and R b each independently have composition of formulas A, B, C, D or a mixture thereof, Z is a moiety having composition selected from the group consisting of formula L, formula M, formula N and a mixture thereof, and the ratio of Type 1 copolyimide to Type 2 copolyimide is greater than 0.2.
2. The membrane of claim 1 in which the Type 1 copolyimide comprises repeating units of formula Ia.

3. The membrane of claim 2 in which R1 is formula Q in about 16% of the repeating units, formula S in about 64% of the repeating units and formula T
in about 20% of the repeating units.
4. The membrane of claim 1 in which the Type 1 copolyimide comprises repeating units of formula Ib
5. The membrane of claim 4 in which R1 is a composition of formula Q in about 1-99 % of the repeating units, and of formula s in a complementary amount totaling 100 % of the repeating units.
6. The membrane of claim 1 in which the Type 1 copolyimide comprises repeating units having composition of formula la and repeating units having composition of formula Ib in which units of formula lb constitute about 1-99 % of the total repeating units of formulas Ia and Ib and in which R1 is a composition of formula Q in about 1-99% of the repeating units, and of formula s in a complementary amount totaling 100 % of the repeating units.
7. The membrane of claim 6 in which the moiety R1 has a composition of formula Q in about 20 % of the repeating units, and of formula s in about 80 %
of the repeating units, and in which repeating units of formula lb are about 40 % of the total of repeating units of formulas la and lb.
8. The membrane of claim 1 in which the ratio of Type 1 copolyimide to Type 2 copolyimide is greater than 1Ø
9. The membrane of claim 1 in which repeating units of formula IIa are at least 25 % of the total repeating units of formula IIa and IIb.
10. The membrane of claim 9 in which repeating units of formula IIa are at least 50% of the total repeating units of formula IIa and IIb.
11. The membrane of claim 1 in which the Type 2 copolyimide is formed by polycondensation of an aromatic amine selected from the group consisting of 2,4-diaminomesitylene, 3,7-diamino-2,8-dimethyldiphenylsulfone and a mixture thereof, and a dianhydride selected from the group consisting of pyromellitic dianhydride, 3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride, 3,3',4,4'-biphenyl tetracarboxylic dianhydride, 4,4'-(2,2,2-trifluoro-1-(trifluoromethyl)ethylidine)bis(1,2-benzene dicarboxylic acid dianhydride) and a mixture thereof.
12. The membrane of claim 1 in which the membrane is an asymmetric membrane.
13. The membrane of claim 12 in which the membrane is a hollow fiber.
14. A method of separating one or more gases from a gas mixture comprising (a) providing a gas separation membrane comprising a blend of at least one polymer of a Type 1 copolyimide and at least one polymer of a Type 2 copolyimide in which the Type 1 copolyimide comprises repeating units of formula I

in which R2 is a moiety having a composition selected from the group consisting of formula A, formula B, formula C and a mixture thereof, Z is a moiety having a composition selected from the group consisting of formula L, formula M, formula N and a mixture thereof; and R1 is a moiety having a composition selected from the group consisting of formula Q, formula S, formula T, and a mixture thereof, in which the Type 2 copolyimide comprises the repeating units of formulas IIa and IIb in which Ar is a moiety having a composition selected from the group consisting of formula U, formula V, and a mixture thereof, and in which X, X1, X2, X3 independently are hydrogen or an alkyl group having 1 to 6 carbon atoms, provided that at least two of X, X1, X2, or X3 on each of U and V are an alkyl group, Ar' is any aromatic moiety, R a and R b each independently have composition of formulas A, B, C, D or a mixture thereof, Z is a moiety having composition selected from the group consisting of formula L, formula M, formula N and a mixture thereof, and the ratio of Type 1 copolyimide to Type 2 copolyimide is greater than 0.2, (b) contacting the gas mixture with one side of the gas separation membrane thereby causing more preferentially permeable gases of the mixture to permeate the membrane faster than less preferentially permeable gases to form a permeate gas mixture enriched in the more preferentially permeable gases on the opposite side of the membrane and a retentate gas mixture depleted in the more preferentially permeable gases on the one side of the membrane, and (c) withdrawing the permeate gas mixture and the retentate gas mixture separately from the membrane.
15. The method of claim 14 in which the gas mixture comprises carbon dioxide and methane.
CA 2500346 2002-12-02 2003-10-27 Polyimide blends for gas separation membranes Active CA2500346C (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US43027502P true 2002-12-02 2002-12-02
US60/430,275 2002-12-02
US10/642,407 2003-08-15
US10/642,407 US7018445B2 (en) 2002-12-02 2003-08-15 Polyimide blends for gas separation membranes
PCT/IB2003/004769 WO2004050223A2 (en) 2002-12-02 2003-10-27 Polyimide blends for gas separation membranes

Publications (2)

Publication Number Publication Date
CA2500346A1 CA2500346A1 (en) 2004-06-17
CA2500346C true CA2500346C (en) 2012-07-17

Family

ID=32474562

Family Applications (1)

Application Number Title Priority Date Filing Date
CA 2500346 Active CA2500346C (en) 2002-12-02 2003-10-27 Polyimide blends for gas separation membranes

Country Status (8)

Country Link
US (1) US7018445B2 (en)
EP (1) EP1567250B1 (en)
JP (1) JP4249138B2 (en)
AT (1) AT429971T (en)
AU (1) AU2003278411A1 (en)
CA (1) CA2500346C (en)
DE (1) DE60327461D1 (en)
WO (1) WO2004050223A2 (en)

Families Citing this family (52)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2435538A1 (en) * 2003-07-18 2005-01-18 Universite Laval Solvent resistant asymmetric integrally skinned membranes
US20050268782A1 (en) * 2004-03-26 2005-12-08 Kulkarni Sudhir S Novel polyimide based mixed matrix membranes
US20050230305A1 (en) * 2004-03-26 2005-10-20 Kulkarni Sudhir S Novel method for forming a mixed matrix composite membrane using washed molecular sieve particles
US7527673B2 (en) * 2004-03-26 2009-05-05 L'air Liquide, Societe Anonyme A Directoire Et Conseil De Surveillance Pour L'etude Et L'exploitation Des Procedes Georges Claude Polyimide based mixed matrix composite membranes
US7476636B2 (en) * 2004-12-03 2009-01-13 L'air Liquide, Societe Anonyme A Directoire Et Conseil De Surveillance Pour L'etude Et L'exploration Des Procedes Georges Claude Method of making mixed matrix membranes using electrostatically stabilized suspensions
US7393383B2 (en) * 2005-01-14 2008-07-01 L'air Liquide, Societe Anonyme A Directoire Et Conseil De Surveillance Pour L'etude Et L'exploitation Des Procedes Georges Claude Separation membrane made from blends of polyimide with polyamide or polyimide-amide polymers
JP5119596B2 (en) * 2005-01-21 2013-01-16 宇部興産株式会社 Method for producing polyimide asymmetric membrane made of multicomponent polyimide
US8101009B2 (en) * 2005-03-02 2012-01-24 L'air Liquide Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Separation membrane by controlled annealing of polyimide polymers
US7422623B2 (en) * 2005-03-02 2008-09-09 L'air Liquide, Societe Anonyme A Directoire Et Conseil De Surveillance Pour L'etude Et L'exploitation Des Procedes Georges Claude Separation membrane by controlled annealing of polyimide polymers
US7485173B1 (en) 2005-12-15 2009-02-03 Uop Llc Cross-linkable and cross-linked mixed matrix membranes and methods of making the same
US20070209505A1 (en) * 2006-03-10 2007-09-13 Chunqing Liu High Flux Mixed Matrix Membranes for Separations
US7897207B2 (en) * 2006-03-10 2011-03-01 Uop Llc Nano-molecular sieve-polymer mixed matrix membranes with significantly improved gas separation performance
US7846496B2 (en) * 2006-03-10 2010-12-07 Uop Llc Mixed matrix membranes incorporating surface-functionalized molecular sieve nanoparticles and methods for making the same
US8083833B2 (en) * 2006-03-10 2011-12-27 Uop Llc Flexible template-directed microporous partially pyrolyzed polymeric membranes
US7637983B1 (en) 2006-06-30 2009-12-29 Uop Llc Metal organic framework—polymer mixed matrix membranes
US7803214B2 (en) * 2006-07-21 2010-09-28 Ube Industries, Ltd. Asymmetric hollow-fiber gas separation membrane, gas separation method and gas separation membrane module
JP5343561B2 (en) * 2006-07-23 2013-11-13 宇部興産株式会社 Method for producing polyimide film made of multi-component polyimide
US7758751B1 (en) 2006-11-29 2010-07-20 Uop Llc UV-cross-linked membranes from polymers of intrinsic microporosity for liquid separations
US7815712B2 (en) * 2006-12-18 2010-10-19 Uop Llc Method of making high performance mixed matrix membranes using suspensions containing polymers and polymer stabilized molecular sieves
US7998246B2 (en) 2006-12-18 2011-08-16 Uop Llc Gas separations using high performance mixed matrix membranes
US20080142440A1 (en) * 2006-12-18 2008-06-19 Chunqing Liu Liquid Separations Using High Performance Mixed Matrix Membranes
US20080143014A1 (en) * 2006-12-18 2008-06-19 Man-Wing Tang Asymmetric Gas Separation Membranes with Superior Capabilities for Gas Separation
US7875758B2 (en) * 2007-01-08 2011-01-25 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes George Claude Systems and methods for the separation of propylene and propane
US20080295691A1 (en) * 2007-06-01 2008-12-04 Chunqing Liu Uv cross-linked polymer functionalized molecular sieve/polymer mixed matrix membranes
US20080296527A1 (en) * 2007-06-01 2008-12-04 Chunqing Liu Uv cross-linked polymer functionalized molecular sieve/polymer mixed matrix membranes
US20080300336A1 (en) * 2007-06-01 2008-12-04 Chunqing Liu Uv cross-linked polymer functionalized molecular sieve/polymer mixed matrix membranes
WO2009059360A1 (en) * 2007-11-05 2009-05-14 Co2Crc Technologies Pty Ltd Gas separation membranes and processes for the manufacture thereof
US8337598B2 (en) 2008-09-05 2012-12-25 Honeywell International Inc. Photo-crosslinked gas selective membranes as part of thin film composite hollow fiber membranes
US7950529B2 (en) * 2008-09-30 2011-05-31 L'air Liquide Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Separation membrane made from blends of polyimides with polyimidazoles
JP5627198B2 (en) * 2009-05-27 2014-11-19 日東電工株式会社 Proton conducting polymer electrolyte membrane, membrane-electrode assembly and polymer electrolyte fuel cell using the same
CN102470329B (en) * 2009-07-23 2015-06-24 赢创纤维有限公司 Polyimide membranes made of polymerization solutions
US20110077446A1 (en) * 2009-09-30 2011-03-31 American Air Liquide, Inc. Membrane Separation of a Mixture of Close Boiling Hydrocarbon Components
US20110138999A1 (en) * 2009-12-15 2011-06-16 Uop Llc Metal organic framework polymer mixed matrix membranes
CN103025796B (en) 2010-04-12 2014-12-31 新加坡国立大学 Polyimide membranes and their preparation
US8366804B2 (en) * 2010-05-28 2013-02-05 Uop Llc High permeance polyimide membranes for air separation
US8911535B2 (en) 2010-10-06 2014-12-16 L'air Liquide Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Carbon dioxide removal process
US8535638B2 (en) 2010-11-11 2013-09-17 Air Liquide Large Industries U.S. Process for recovering hydrogen and carbon dioxide
US20120118011A1 (en) 2010-11-11 2012-05-17 Air Liquide Large Industries U.S. Lp Process For The Production Of Hydrogen And Carbon Dioxide
US20120291481A1 (en) 2011-05-18 2012-11-22 Air Liquide Large Industries U.S. Lp Process For Recovering Hydrogen And Carbon Dioxide
US20120291484A1 (en) 2011-05-18 2012-11-22 Air Liquide Large Industries U.S. Lp Process For The Production Of Hydrogen And Carbon Dioxide
US8614288B2 (en) * 2011-06-17 2013-12-24 Uop Llc Polyimide gas separation membranes
EP2682364A1 (en) 2012-07-04 2014-01-08 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Process for recovering hydrogen and capturing carbon dioxide
EP2733115A1 (en) 2012-11-14 2014-05-21 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Process for recovering hydrogen and carbon dioxide
EA030486B1 (en) * 2013-06-21 2018-08-31 Эвоник Фибрес Гмбх Method for producing polyimide membranes
JP2015083296A (en) * 2013-09-20 2015-04-30 富士フイルム株式会社 Gas separation membrane, gas separation module, gas separation device, and gas separation method
US9522364B2 (en) 2013-12-16 2016-12-20 Sabic Global Technologies B.V. Treated mixed matrix polymeric membranes
CN106255544A (en) 2013-12-16 2016-12-21 沙特基础工业全球技术公司 UV processes and the polymeric film of heat treatment
US9308487B1 (en) * 2014-09-25 2016-04-12 Uop Llc Polyimide blend membranes for gas separations
US9308499B1 (en) * 2014-09-25 2016-04-12 Uop Llc Polyimide blend membranes for gas separations
US9233344B1 (en) * 2014-09-29 2016-01-12 Uop Llc High selectivity polyimide membrane for natural gas upgrading and hydrogen purification
US20160184771A1 (en) 2014-12-31 2016-06-30 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Polyimide membrane for h2s removal
WO2017002407A1 (en) * 2015-06-30 2017-01-05 富士フイルム株式会社 Gas separation membrane, gas separation module, gas separation device, gas separation method, and polyimide compound

Family Cites Families (43)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2193634B1 (en) * 1972-07-20 1980-03-28 Du Pont
US4080744A (en) * 1976-06-22 1978-03-28 E. I. Du Pont De Nemours And Company Gas separation membrane drying with water replacement liquid
US4120098A (en) * 1976-06-22 1978-10-17 E. I. Du Pont De Nemours And Company Solvent exchange drying of membranes for gas separation
EP0023406B1 (en) * 1979-07-26 1983-04-13 Ube Industries, Ltd. Process for preparing aromatic polyimide semipermeable membranes
JPS6242045B2 (en) * 1984-06-20 1987-09-07 Kogyo Gijutsuin
JPH0247931B2 (en) * 1984-11-30 1990-10-23 Ube Industries GASUBUNRIHORIIMIDOMAKU
US4705540A (en) * 1986-04-17 1987-11-10 E. I. Du Pont De Nemours And Company Polyimide gas separation membranes
US5055116A (en) * 1989-05-22 1991-10-08 Hoechst Celanese Corp. Gas separation membranes comprising miscible blends of polyimide polymers
US4717393A (en) * 1986-10-27 1988-01-05 E. I. Du Pont De Nemours And Company Polyimide gas separation membranes
US4880442A (en) * 1987-12-22 1989-11-14 E. I. Du Pont De Nemours And Company Polyimide gas separation membranes
EP0391699B1 (en) * 1989-04-07 1994-12-14 Ube Industries, Ltd. Pervaporation method of selectively separating water from an organic material aqueous solution through aromatic imide polymer asymmetric membrane
JPH0342026A (en) * 1989-07-06 1991-02-22 Mitsubishi Kasei Corp Production of polyimide separation film
FR2650757B1 (en) * 1989-08-11 1992-06-05 Inst Francais Du Petrole Gas separation membrane
FR2650755B1 (en) * 1989-08-14 1991-10-31 Inst Francais Du Petrole Gas separation membrane
US5015270A (en) * 1989-10-10 1991-05-14 E. I. Du Pont De Nemours And Company Phenylindane-containing polyimide gas separation membranes
US5061298A (en) * 1990-06-13 1991-10-29 Air Products And Chemicals, Inc. Gas separating membranes formed from blends of polyimide polymers
US5178650A (en) * 1990-11-30 1993-01-12 E. I. Du Pont De Nemours And Company Polyimide gas separation membranes and process of using same
US5085676A (en) * 1990-12-04 1992-02-04 E. I. Du Pont De Nemours And Company Novel multicomponent fluid separation membranes
JP2588806B2 (en) * 1991-09-10 1997-03-12 宇部興産株式会社 Gas separation hollow fiber membrane and method for producing the same
US5234471A (en) * 1992-02-04 1993-08-10 E. I. Du Pont De Nemours And Company Polyimide gas separation membranes for carbon dioxide enrichment
US5248319A (en) * 1992-09-02 1993-09-28 E. I. Du Pont De Nemours And Company Gas separation membranes made from blends of aromatic polyamide, polymide or polyamide-imide polymers
US5266100A (en) * 1992-09-02 1993-11-30 E. I. Du Pont De Nemours And Company Alkyl substituted polyimide, polyamide and polyamide-imide gas separation membranes
US5232472A (en) * 1992-11-03 1993-08-03 E. I. Du Pont De Nemours And Company Polyimide and polyamide-imide gas separation membranes
US5264166A (en) * 1993-04-23 1993-11-23 W. R. Grace & Co.-Conn. Polyimide membrane for separation of solvents from lube oil
FR2710549B1 (en) * 1993-09-27 1996-06-21 Inst Francais Du Petrole High selectivity asymmetric membranes for the separation of gases and a process for their production.
US5917137A (en) * 1993-10-19 1999-06-29 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Gas separation membranes of blends of polyethersulfones with aromatic polyimides
DE69433127T2 (en) * 1993-10-19 2004-07-08 L'Air Liquide, S.A. a Directoire et Conseil de Surveillance pour l'Etude et l'Exploitation des Procédés Georges Claude Mixtures of polyether sulfones and aromatic polyimides, polyamides or polyamide-imides and gas separation membranes made from them
US5443728A (en) * 1994-04-28 1995-08-22 Praxair Technology, Inc. Method of preparing membranes from blends of polyetherimide and polyimide polymers
US5647894A (en) * 1994-06-08 1997-07-15 Nitto Denko Corporation Gas separating composite membrane and process for producing the same
US5749943A (en) * 1995-02-27 1998-05-12 Petroleum Energy Center Method of selectively separating unsaturated hydrocarbon
US5635067A (en) * 1995-03-14 1997-06-03 Praxair Technology, Inc. Fluid separation membranes prepared from blends of polyimide polymers
US5618334A (en) * 1995-06-30 1997-04-08 Praxair Technology, Inc. Sulfonated polyimide gas separation membranes
FR2748485B1 (en) * 1996-05-07 1998-08-07 Commissariat Energie Atomique SULPHONATED POLYIMIDES, MEMBRANES PREPARED THEREWITH, AND FUEL CELL DEVICE COMPRISING SUCH MEMBRANES
US5969087A (en) * 1997-04-04 1999-10-19 Nitto Denko Corporation Polyimide, a method for manufacturing the same, a gas separation membrane using the polyimide and a method for manufacturing the same
US5922791A (en) * 1997-12-19 1999-07-13 L'air Liquide Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Polymer blend membranes with improved mechanical properties
US6497747B1 (en) * 1999-09-24 2002-12-24 Praxair Technology, Inc. Production and use of improved polyimide separation membranes
EP1118371B1 (en) * 2000-01-19 2007-04-11 Ube Industries, Ltd. Gas separation membrane and its use
US6383258B1 (en) * 2000-12-19 2002-05-07 L'air Liquide Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Copolyimide gas separation membranes
US6602415B2 (en) * 2001-02-09 2003-08-05 Board Of Regents, The University Of Texas Polymeric membrane for separation of fluids under elevated temperature and/or pressure conditions
JP2003062422A (en) * 2001-08-27 2003-03-04 Inst Of Physical & Chemical Res Gas separation membrane and method for manufacturing the same
US20030131731A1 (en) * 2001-12-20 2003-07-17 Koros William J. Crosslinked and crosslinkable hollow fiber mixed matrix membrane and method of making same
US20030126990A1 (en) * 2001-12-20 2003-07-10 Koros William J. Crosslinked and crosslinkable hollow fiber membrane and method of making same
US7169885B2 (en) * 2003-03-13 2007-01-30 National University Of Singapore Polyimide membranes

Also Published As

Publication number Publication date
JP4249138B2 (en) 2009-04-02
EP1567250B1 (en) 2009-04-29
EP1567250A2 (en) 2005-08-31
AU2003278411A8 (en) 2004-06-23
AU2003278411A1 (en) 2004-06-23
JP2006507939A (en) 2006-03-09
US20040107830A1 (en) 2004-06-10
WO2004050223A3 (en) 2005-04-28
CA2500346A1 (en) 2004-06-17
AT429971T (en) 2009-05-15
DE60327461D1 (en) 2009-06-10
US7018445B2 (en) 2006-03-28
WO2004050223A2 (en) 2004-06-17

Similar Documents

Publication Publication Date Title
Qiu et al. Gas separation performance of 6FDA-based polyimides with different chemical structures
Alaslai et al. Pure-and mixed-gas permeation properties of highly selective and plasticization resistant hydroxyl-diamine-based 6FDA polyimides for CO2/CH4 separation
Scholes et al. Membrane gas separation applications in natural gas processing
Scholes et al. CO2 capture from pre-combustion processes—Strategies for membrane gas separation
Li et al. Mechanically robust thermally rearranged (TR) polymer membranes with spirobisindane for gas separation
Hosseini et al. Gas separation membranes developed through integration of polymer blending and dual-layer hollow fiber spinning process for hydrogen and natural gas enrichments
JP5567211B2 (en) High permeance polyimide membrane for air separation
JP5981989B2 (en) Polyimide gas separation membrane
Chen et al. High performance composite hollow fiber membranes for CO2/H2 and CO2/N2 separation
EP0422885B1 (en) Phenylindane-containing polyimide gas separation membranes
US5591250A (en) Material and process for separating carbon dioxide from methane
Tin et al. Separation of CO2/CH4 through carbon molecular sieve membranes derived from P84 polyimide
Kumbharkar et al. High performance polybenzimidazole based asymmetric hollow fibre membranes for H2/CO2 separation
AU719591B2 (en) Gas separations utilizing glassy polymer membranes at sub-ambient temperatures
US5074891A (en) Method of gas separation and membranes therefor
KR101359166B1 (en) Blend polymer membranes comprising thermally rearranged polymers derived from aromatic pol yimides containing ortho-positioned functional groups
AU628774B2 (en) Gas separation material
JP2858865B2 (en) Gas separation membrane of copolyimide derived from substituted phenylenediamine and substituted methylenedianiline
Brunetti et al. Membrane technologies for CO2 separation
Powell et al. Polymeric CO2/N2 gas separation membranes for the capture of carbon dioxide from power plant flue gases
US8132678B2 (en) Polybenzoxazole polymer-based mixed matrix membranes
Stern et al. Structure/permeability relationships of polyimide membranes. Applications to the separation of gas mixtures
US8613362B2 (en) Polymer membranes derived from aromatic polyimide membranes
EP0321638B1 (en) Polyimide gas separation membranes
CN1248773C (en) Copolyimide gas separation membranes

Legal Events

Date Code Title Description
EEER Examination request